As counterintuitive as it may sound, newborn babies and infants need to be exposed to certain bacteria and infections in order to avoid developing childhood leukemia later on in life.

That’s according to a new study that suggests children with a specific genetic mutation that predisposes them to acute lymphoblastic leukemia (ALL), the most common form of childhood cancer, are more likely to develop the disease if they lived in germ-free environments and had little interaction with other children.

Mel Greaves, the study’s author and a professor of Cell Biology at the Institute of Cancer Research in London, said he and his team studied more than 30 years of research on what causes childhood leukemia. He said they discovered a higher prevalence of the disease in countries with higher socio-economic development and affluence.

“That didn’t make sense in terms of infection because normally infectious diseases track in the opposite direction so I inverted the problem and thought, ‘Well, maybe it’s lack of infection that’s critical,’” he explained to CTV News Channel on Wednesday.

The researchers found that children born with the genetic mutation who had less exposure to infectious bacteria and viruses early on life were more likely to develop childhood leukemia.

Greaves stressed, however, that it doesn’t mean families with clean kitchens or who prevent their children from playing in the dirt are depriving them of essential exposure to infections. Instead, the study author said it has more to do with “broad-sweeping social changes in western societies.”

He pointed to the example of families in these countries having fewer offspring and therefore, the children have less exposure to microbes from their siblings. He also said less time breastfeeding and fewer social contacts may contribute to children’s decreased exposure to infections.

“At birth, children pick up microbes from the mother through breastfeeding and from social contacts with other children, so it’s really the way those aspects of our social behaviour have changed that seems to be elevating the risk,” he explained.

Greaves said the findings offer good news for the prevention of childhood leukemia, which he said is already 90 per cent curable.

The study was published Monday in the journal Nature Reviews Cancer.